This carb does use a pointed screw with the tip made of a different material than the screw, maybe Viton? I don't believe the drain doubles as an overflow in this carb. I don't recall seeing an o-ring on the drain screw so maybe if it is supposed to have one, I lost it when I was taking the carb apart to clean it. I'll pull the screw and see if there is any obvious place for an o-ring to be. Thanks.